Plastic laminate structure consisting of a plastic film laminated to a substrate with a resin impregnated paper intermediate layer

ABSTRACT

Laminated structures are disclosed wherein a reverse printed film of plastic such as polyvinyl chloride, Tedlar or polytetrafluoroethylene is joined to a substrate by means of a thermoset resin impregnated paper layer.

United States Patent Long et al.

15 3,663,353 14 1 May 16, 1972 PLASTIC LAMINATE STRUCTURE CONSISTING OFA PLASTIC FILM LAMINATED TO A SUBSTRATE WITH A RESIN IMPREGNATED PAPERINTERMEDIATE LAYER Jack D. Long, Cleveland, Ohio; David Richards,Lunenburg, Mass.

Inventors:

Assignee: Fitchburg Paper Company, Fitchburg,

Mass.

Filed: June 1, 1970 Appl. No.: 41,740

Related US. Application Data Continuation of Ser. No. 602,797, Dec. 19,1966, abandoned.

[56] References Cited UNITED STATES PATENTS 2,571,962 10/1951 Smith eta1 156/277 2,696,452 12/1954 Trepp 156 240 3,218,225 1 1/1965Petropoulos 161/248 3,294,619 12/1966 Noland ..161/165 3,340,137 9/1967Kamal ..-...16l/184 3,403,071 9/1968 Perry et al. ..161/189 3,418,18912/1968 Grosheim ..156/277 3,488,249 l/1970 Wolinski ..161/189 X PrimaryExaminer-John T. Goolkasian Assistant Examiner-D. .1 FritschAtzorneyArthur T. Groeninger, Norman Friedman, Stephen E. Feldman, ElmerW. Edwards and Morris 1. Pollack ABSTRACT 1 Claims, 1 Drawing FigurePEI/5,955 Rem/7'50 PLAST/C F/L/f 0? 67/557; 506/, AS oA/ zAsr/c/zia -40pau w/wz CHLOP/D PLASTIC LAMINATE STRUCTURE CONSISTING OF A PLASTIC FILMLAMINATED TO A SUBSTRATE WITH A RESIN IMPREGNATED PAPER INTERMEDIATELAYER This Application is a continuation of copending application, Ser.No. 602,797 filed Dec. 19, 1966 and now abandoned.

PLASTIC LAMINATE STRUCTURE This invention relates to laminatestructures, particularly plastic laminate structures. More specifically,this invention is directed to a laminate structure containing as onecomponent or layer thereof a plasticized or unplasticized film of apolymeric material or plastic, such as polyvinyl chloride and Tedlar (apolyvinyl fluoride).

In accordance with one embodiment this invention is directed to a methodof preparing a plastic laminate structure containing a film ofunplasticized or plasticized polymeric material, such as polyvinylchloride. In accordance with another embodiment this invention isdirected to a method of joining or incorporating a film or sheet ofplastic, such as polyvinyl chloride, in a laminate structure. Inaccordance with yet another embodiment this invention is directed to aunitary laminate structure containing a film or sheet of polymericmaterial or plastic joined or united to a layer containing thermosetresin.

Plastic materials are useful materials for construction. For example,plastics, such as Tedlar and polyvinyl chloride, are desirable materialsto be incorporated in laminate structures, particularly as a top layer,since these materials are wear resistant, stain resistant, weatherresistant and are capable of being treated to yield an attractiveappearance. Unfortunately, however, these materials are relativelydifficult to incorporate in laminate structures. In the past it has beennecessary to apply an adhesive to a surface of the plastic film or sheetbefore it could be incorporated in a laminate structure. The operationinvolving the application of an adhesive layer to a plastic film orsheet adds to the expense of the resulting produced laminate structureand tends, in some instances, to interfere with the attractiveness ofthe finished product. Also, equipment for applying adhesive to theplastic film or sheet, followed by the incorporation of the resultingadhesive coated film or sheet in a laminate structure, gives rise tolimitations with respect to the size and strength and other propertiesof the resulting produced laminate structure.

It is an object of this invention to provide a laminate structureincluding a film or sheet of plastic, such as Tedlar and polyvinylchloride, as a component or layer of the laminate structure without atthe same time including or incorporating an adhesive layer or coatingfor the plastic component or layer of the laminate structure.

It is another object of this invention to provide a plastic laminatestructure containing as an exposed or top layer thereof a film or sheetof plastic laminated or joined in a unitary structure with a thermosetresin-impregnated intermediate layer.

How these and other objects of this invention are achieved will becomeapparent in the light of the accompanying disclosure made with referenceto the accompanying drawing wherein there is schematically illustrated aplastic laminate structure in accordance with this invention. In atleast one embodiment of the practices of this invention at least one ofthe foregoing objects will be achieved.

A plastic laminate structure in accordance with one embodiment of thisinvention comprises a film or sheet of plastic or polymeric material,such as Tedlar and unplasticized polyvinyl chloride, and a substratewherein the film of plastic or polymeric material is joined to saidsubstrate by means of an intermediate layer of porous and/or fibrousmaterial, such as paper, e.g. alpha-cellulose paper and kraft paper,impregnated with a thermoset resin, the thermoset resin in saidintermediate layer serving to join said film or sheet of plastic to saidintermediate layer and serving to join said substrate to saidintermediate layer, thereby providing an integral plastic laminatestructure.

Referring now to the drawing, there is illustrated therein an example ofa plastic laminate structure in accordance with this invention. Asillustrated in the drawing, an exposed or top layer 10 of the plasticlaminate structure comprises reverse printed unplasticized polyvinylchloride which is joined or united to an intermediate porous and/orfibrous layer 11, such as paper, e.g. kraft paper, which is saturatedwith a thermoset resin, such as thermoset epoxy, phenolic, or melamineresin. lntennediate layer 11 isalso joined or united to substrate 12,likewise by means of the thermoset resin. Substrate 12 may comprisesubstantially any substrate, such as a substantially rigid substrate,e.g. a metal or composite substrate, hardboard, plywood, pressed board,flake board and particle board.

The top plastic layer 10 of the plastic laminate structure is desirably,in accordance with one embodiment of the invention, made up ofunplasticized polyvinyl chloride. Other synthetic resin plastic orpolymeric materials, plasticized or unplasticized, are also useful, suchas Tedlar and a polytetrafiuoroethylene manufactured by El. duPont deNemours & Co. Other plastic and polymeric materials, and paper made upof cellulosic and/or synthetic fibers, depending upon the physicalproperties desired in the finished product, are also useful.

As the intermediate layer making up the plastic laminate structure inaccordance with this invention substantially any porous and/or fibrousmaterial may be employed. Particularly suitable is paper, e.g. kraftpaper and alpha-cellulose paper and other papers useful as barrier oroverlay sheets in laminate manufactures.

The thermoset resin with which the intermediate layer 11 is impregnatedmay be derived from substantially any thermosetting resin. Thermosettingresins useful in the manufacture of plastic laminate structures inaccordance with this invention include thermosetting phenolic resins,e.g. phenol formaldehyde resins, the thermosettingaminotriazine-aldehyde resins, such as melamine formaldehyde resins,thermosetting polyester resins, thermosetting epoxy resins,thermosetting silicone resins, diallyl phthalate and the like.

Various materials may be employed as substrate 12 in accordance withthis invention. Particularly useful are the substantially rigidsubstrates, such as hardboard, plywood and particle board. Metalsubstrates, such as aluminum and steel, and suitably treated papersubstrates may also be employed.

In the preparation of a plastic laminate structure in accordance withthis invention the intermediate layer 1 1, such as kraft paper, issubstantially saturated with a thermosetting resin. Desirably, thesaturated paper should contain at least about 25 percent by weight resinand, after removal of excess resin, is dried before the resin ispartially cured.

There is then applied to the intermediate layer, now containingpartially cured thermosetting resin, the top layer or film 10, such as afilm or sheet of unplasticized polyvinyl chloride having a thickness inthe range from about 0.5 mil to about 15 mils, more or less, usually athickness in the range 2-10 mils. The resulting composite is thenapplied or suitably joined to the substrate and the resulting assemplythen subjected to conditions effective to fully cure the partially curedresin. Upon curing the resulting thermoset resin serves to join or unitethe top layer or film of unplasticized polyvinyl chloride to theintermediate paper layer and also serves to join or unite the substrateto the intermediate paper layer.

Suitable conditions for curing the partially cured thermosetting resinare well known and, by way of example, include a pressure in the rangefrom about 800 to about 1,500 psi, a temperature in the range from about260 to about 300 F. Higher and lower pressures and higher and lowertemperatures in combination with longer and shorter cured periods may beemployed depending upon 'the resin employed and other factors.

Generally, an overall commercial laminating-curing operation inaccordance with this invention requires a period of time in the rangefrom about 25 minutes to about 1 hour, more or less. In thelaminating-curing operation the temperature employed is usually thecontrolling factor. Usually in a commercial laminating,curing operationone third of the time is required to get the laminating press up totemperature, another one third for the curing operation and theremaining one third for cooling the press and removing the resultingplastic laminate structure. By way of example, the composite laminate ofplastic, partially cured intermediate layer and substrate would beheated under pressure at a temperature in the range 260-300 F. for about10-25 minutes and then cooled to about room temperature or a temperaturein the range lO-160 F. over a period of time of about -15 minutes andthen released from the laminating press.

The practices of this invention are particularly useful in connectionwith the manufacture of high or low pressure laminates. At present, themanufacturer of high or low pressure laminates cannot handle thelamination of plastic films, such as unplasticized polyvinyl film, to asubstrate, such as hardboard, plywood, particle board and the like, forvertical surfacing to complement a horizontal surfacing product becausepresent techniques require the roll application of adhesive for joiningthe plastic film.

In accordance with another embodiment of the practice of this invention,there is produced a laminate structure made up of a plastic film, suchas unplasticized polyvinyl film, applied or joined to paper, e.g. kraftpaper, impregnated with cured thermosetting resin. This two layerlaminate structure is prepared by laminating a film of plastic, such asTedlar, polyvinyl chloride and the like to paper impregnated with athermosetting resin, uncured or partially cured, followed by curing toproduce the laminate structure desired.

The practice of this invention, as indicated hereinabove, permits theuse of a decorative plastic film or sheet top coat or layer whereindecorative features are imparted, such as by reverse printing, to theplastic film and applying or joining the decorated surface of theplastic film directly to the intermediate layer saturated with theresin.

In accordance with another embodiment of the practices of this inventionthere may be included as the intermediate layer, see layer 11 of thedrawing, one or more resin impregnated fibrous or paper sheets,including a barrier sheet. The resin content of the intermediate layeror layers is usually in the range 25-70 percent by weight resin.

In accordance with yet another embodiment of the practices of thisinvention there may be produced a five layer laminate structurecomprising a plastic toplayer, a paper or intermediate layer impregnatedwith thermoset resin, a substrate or rigid core material, such asplywood, hardboard, particle board or metal, another intermediate layer,such as paper, impregnated with thermoset resin and a bottom layer orfilm of plastic.

As will be apparent to those skilled in the art in the light of theforegoing disclosure many modifications, alterations and substitutionsare possible in the practice of this invention without departing fromthe spirit or scope thereof.

We claim:

1. A plastic laminate structure consisting essentially of a film ofreverse printed polyvinylchloride and a substrate, said film beingjoined to said substrate by means of a layer of paper impregnated with athermoset resin; the resin content of said layer being between 25 70percent by weight, said substrate being selected from the groupconsisting of metal, hardboard, plywood, pressed board, flake board andparticle board, said film of plastic has a thickness in the range fromabout 0.5 mil to about 15 mils, said thermoset resin is selected fromthe group consisting of a thermoset phenolic resin, a thermoset melamineresin, a thermoset epoxy resin, a thermoset silicone resin, a thermosetpolyester resin and thermoset diallyl phthalate.

partially cured thermosetting l i l i i

